Electromagnetic clutch apparatus



July zo, 1943.

l. o, yMINER .ELECTROMAGNETIC CLUTCH APPARATUS Filed April 10, 1940 2sheets-sheet 1 n "Pff ATTORNEY July 20, 1943. v Y o. MiNER' `2,324,599

` ELEc'rnoMAGNETIc CLUTCH APPARATUS .r l

l Filed April 10,V 1940 2 `sheets-sheet 2 v INVENTQR ATTORNEY PatentedJuly 20, 1943 Y LEc'rRoMAGNE'rIc CLUTCH APPARATUS Irving 0. Miner, EastProvidence, R. I., assignor to Builders Iron Foundry, Providence, R. I.,a corporation of Rhode Island Application A-pril 10, 1940, Serial No.328,834

' s claims.

This invention relates to an electromagnetic clutch mechanism. An objectis the provision of such a mechanism of simple and rugged constructionwhich may be employed to distinct advantage with alternating currents.

. An important feature of the invention resides in an electromagneticclutch mechanism operable promptly and efllciently without objectionablevibration. or chattering," notwithstanding the employment of alternatingcurrent.

The invention has been developed in conjunction with a telemetricreceiver apparatus having distinct advantages, and is accordinglyillustrated as part of such apparatus.

The invention also comprises further features which will be hereinafterdescribed and claimed.

In the accompanying drawings:

Fig. l is a view, partlyin vertical section and partly in sideelevation, illustrating an embodiment of the invention.

Fig. 2 is a iront elevational view showing a portion of the apparatusillustrated in Figure 1.

Fig. 3 is a view in elevation of mechanism at the rear of the apparatusin Fig. 1.

Fig. 4 is a detail isometric view of the armature of one of theelectromagnets.

Referring tothe drawings, the invention is shown in connection with atelemetric receiver, connected to an alternating current circuit whichincludes a transmitter of any suitable or well known type. Saidtransmitter, as shown, may comprise a cam 2 which is continuouslyrotated at substantially constant speed by a synchronous motor 3connected to the alternating current mains 4 and 5. A contactor 6,engageable by the face of said cam during each cycle of rotation of thelatter, is carried by a rod 1, vertically movable between pairs' ofguide rollers 8; said rod being positioned, either manually orautomatically, in accordance with values o! a quantity such, forexample,as pressure, temperature, or iiow rate of a liquid. The contactor isconnected by wire 9 with one terminal ofrelay magnet I0, the otherterminal of which is connected by wire II with the main 4. `Current frommain is led to the cam 2 through brush I2.

It will thus be seen that in each cycle oi rotation of the transmittercam 2 a circuit is closed through the relay magnet I0 for a timeproportional to the duration of engagement between said cam and thecontactor 6, or. in other words, for a time corresponding to the valueof the quantity in accordance with which said contactor 1S positioned.During the remainder of the cycle of rotation of said cam, said magnetIII is de-energized.

The receiver apparatus is shown as comprising a suitable frame I3 in therearpanel I4 of which are mounted a pair of ybearing sleeves I5, I6.Journaled on said bearing sleeves are a pair of intermeshing gears I'I,I3; respectively. Said gears areI rotated continuously at substantiallyconstant speed, and in opposite directions, by synchronous motor I9,through a pinion 20 which engages the gear I1. Motor I9 is connected bywires 2|, 22 with the alternating current mains 4, 5.

Secured to the gear I1 is a-shell or casing 23, which has a bearingportion 23' fitted over a hub I1' of said` gear and also over a frontendiiange of the sleeve I5, as shown. Within said shell is a stationarycoil24, supported in any suitable way, as by a bracket 25 fastened to theframe I3.

A similar shell 26 is secured to gear I8 and has a bearing portion 26'fitted over hub I8' of said gear and ove'r the front end ange of sleeveI8. A stationary coil 21 is supported within-said shell 26 in anyconvenient way, as through a bracket 28 secured to said frame I3. vThebrackets 25,

28 are of. insulating material, although they may be of metal andsuitably insulated from the frame I3.

Armatures 29, 30 cooperate with the respective coils 24, 21, and aremovable upon energization of said coils into engagement with thecorresponding shells 23, 28, so as to rotate withthe respective gears I1and I8. The armature 29, as shown, is fastened to a rod or spindle 3|which extends through, and is slidably supported in, the sleeve I5.Similarly, the armature 30-is fastened i to the rod or spindle 32,'projecting through and slidably mounted in the sleeve I6. Said spindles3| and 32 preferably engage Within said sleeves with a somewhat loosefit to facilitate seating of each armature against the adjacent shellwithout being restricted by a tight nt of the spindle in the sleeve.

The shells 23 and 26, gears II and I8, hubs I1 and IB', sleeves I5 andI6, and spindles 3| and 32 are of magnetic material providing paths formagnetic ux through the respective armatures 29 and 30 when thecorresponding coils are energized. The armatures are likewise ofmagnetic material (excepting for certain non-magnetic insertshereinafter described) so that upon energization of either of said coilsthe armature lassociated therewith is drawn into firm engage- Ament withthe corresponding shell and rotates therewith throughout the period of'energizauon of said coil. Each armature (Figures 2 and 4) comprises amain body portion, one end of which is slotted,

. at 33, 33, to provide three separate paths for the magnetic ilux. i.e., through the side prongs 34, 34, and the central portion of saidslotted end. y Said central portion 35 isoffset with re-l spect to saidprongs 34, 34. and carries a shading coil 38, which retards the buildinglup oi the magnetism in said `central portion so that the magnetismtherein is out of phase with that in the prongs 34, 34, so that magneticux is continuously present in the varmature during energization of theassociated coil 24 or 21, regardless of the alternations oi' thecurrent. 'As shown, the projections 34, 34, and-35 are odset slightlyoutwardly with respect to the lmain or body portion of the armaturaandhave lips 34", 34' and 35' `extending inwardly at their free ends.

Between the lips 34', 34', of prongs 34 and the lip 35' oi' the centralportion 35, there are inter' posed a pair of inserts 31, 31, ofnon-magnetic material, such as brass or copper, which may be silversoldered in place. I have found that the provision ,of these inserts,which physically tie together the portions 34, 34 and 35, eliminateundesirable noise which occurs when said portions are entirely free attheir ends and which appears to be caused by each t such parts vibratingagainst the edge of the shell as its magnetism alternates. With saidinserts however, the armature, when attracted, rests quietly against theedge of the shell.

It willbe further observed that each armature that the armature bearsequally against the opposite portions 'of the outer rim at the same timethat it bears against the central bearing sleeve 23' or 28 of saidshell. With the construction shown, the armature can bear readilyagainst said bearing sleeve at the same time that one J end of saidarmature bears against the outer rim oi the shell, which is entirelyadequate for causing rotation of the armature with the shell andassociated gear, while at the same time objectionable noise is avoidedwithout the necessity of attempting to provide a perfect iit between thearmature and opposite portions of the outer rim.

Each of the magnet coils has a terminal connected to the main 4, bywires 38 and 39 respectively. The opposite .terminals of said coils areconnected, by wires 40, 4|, to a pair of contacts 42, 43. The latter areengageable alternately by a contact 44 carried by a blade 45 having anarmature 46, said contact and blade being connected to the current main5. When the magnet I9 is energized in each cycle oi' rotation of thetransmitter cam 2, the armature 43 is attracted and contact 44 isengaged with contact 43, therecontact 44 into engagement with contact42,"de 15 energizing coil 23 and energizing coil 24, "with consequentattraction of armature 29 into engagement with shell 23.

The rotation of the armatures 29 and 30 with the corresponding gears I1and I8 is adapted to position an element, such as an indicator orcontrolling member, in accordance with the quantity values correspondingto the transmitted signals. While said element might, for example, be inthe form of a recording pen, or a member for operating a valve, suchelement is here shown for illustrative purposes as an indicator 48having a hub 43 pivoted on the iront frame I3, and movable along asuitable scale 50. The pivotal axis of said indicator 48, as shown, iscoaxial with that of the armature 29 on the rod 3|. A resilient washer5I (Fig. 1) bears against said hub 49 and maintains the element 48frictionally in the position to which it is' moved under control oi thearmatures 29 and 33. Y,

` An arm 52 extends from the armature29 and carries a lateral projection52' which extends into a position overlying the indicator 48. Similarly,an arm 53. pivotally mounted on a block 54 coaxially with `the pivot ofsaid indicator 48, carries a lateral projection 53"which extends beneath"said indicator; said arm 53 being connected by link 55 with an arm 53which extends from the armature 30.

It will be noted that the center of gravity of each armature 29 and 30is not in its laxis of rotation, so that, when either armature is re-fleased by de-energization of its associated clutch coil 24 or 21, saidarmature may be returned by gravity to its rest or zero position, inwhich it engages a stop screw 51 or 58 (Fig. 2). I have,

' however, provided spring means for supplementing the action of gravityand imparting a more rapid and positive action to restore said armatures'to said positionsJ To this end, each of the rods or spindles 3| and -32to which the respective armatures 29 and 38 are secured, has connectedto its rear end a corresponding one of a pair of spiral springs 59, 68.Spring 59 tends to turn the shaft 3| and armature 29 counter-clockwiseasviewed in Figis attracted into'engagement with the shell 26,. thespindle 32 acts upon the adjacent end of the beam 62 .to throw said endoutwardly, thereby rocking the upper end of said beam inwardly to thrustthe spindle; 3| in the corresponding direction and insure positivedisengagement of armature 29 from shell 23. The pivot for said walkingbeam may comprise an eccentric screw 63, enabling the attainment of avery fine adjustment of said beam in relation to the rods or spindles3|, 32. f

From the foregoing description, it will be apparent that in each cycleof rotation of the transmitter cam 2 the magnet coil 21 is energized forthe period of engagement between said cam and the contacter 6, or, inother words, foi' a time corresponding to the quantity value representedby the position of said contactar. The clutch armature 30 is engagedwith shell 28 and rotates with gear I8 for this same period. saidarmature i 2,324,159Q4 turning counter-clockwise from `its zerovposition in Figure 2 and moving the `projection 53' upwardly into aposition corresponding `to said quantity value. If the pointer 48indicates a reading lower than said value, saidlprojection 53',duringits upward movement, encounters said f pointer 48 and moves the latterupwardly until it arrives at a position indicating said value. If, onthe other hand, said indicator designates a higher value, theprojectionl 53' moves'idly without shifting the indicator. If saidpointer indicated the proper value prior to said `upward movement ofsaid projection 53' the latterA simply .teringy are obviated despite thegenerally desirable 'employment'of alternating current.

Theterms and expressions which I have employed are used as terms ofdescription and not ofV limitation, and 1 have no intention, in the useof suchA terms and expressions, of excluding any equivalents of thefeatures shownandV described or portions'thereof, but recognize thatvarious modifications are possible within the scope of the inventionclaimed.. i

I claim:` 1 1; An armature for an alternating current electromagnet,said armature'comprising a memengages said pointer at the end of vsaidupward movement, without disturbing the pointer.

When, now, the cam 2 moves out of engagement with the contactor 6, thecoil 21. is de-energized and coil 24 is energized. `Armature 29 is nowengaged with shell 23 and rotates clockwise from its'zero position inFigure 2, moving the arm 52 and projection 52" downwardly throughout'the i period in which said lcam and contactor` are out of engagement.When said armature 29 is drawn into engagement with vsaid shell 23, therod 3l is shifted rearwardly, actuatingthe walking beam 62 to thrust therod 32 forwardly and thereby positively disengaging the armature 39 fromshell 26, whereupon said armature` 30, together with projection 53', isrestored to its zero position by gravity, assisted by spring 60. 'Theprojection 52 moves downwardly until the coil 21 is again energized, andit the pointer 48 indicates a reading higher than the valuecorresponding to the position of the contactor 6, said projectionwillengage said pointer andmove it downwardly until said pointer indicatesthe proper value. On the other hand, if saidpointer is already at theproper value, the projection 52' simply engages said pointer at the endof said downward movement, without moving the pointer.

Whenthe cam 2vnext engages the contactar E, the coil 24 is de-energizedand coil 21 is again energized, attracting armature 30 into engage-`beam 62 through spindle 32 to 'throw the arm-ature 29 positively out ofengagement with shell 23, whereupon said armature, together withprojection 52', is restored to its zero position by gravity, assisted byspring 59. The cycle above.

described, is nowrepeated, the respective projections 52 and 63' movingalternately in oppoi site directionsand through complemental extogether.

berhaving at one end a central projection, a pair of other projectionsat opposite sides of said cen-i trai projection, said projectionsproviding separate paths for magnetic iiux, each oi' said pro'-fjections having a lip at its free end, said central projection beingoiset with relation to said side projections and carrying a shadingcoil, and inserts of non-magnetic metal positioned between the lips-ofsaid projections for tying the same 2. Incombination, a driving member,a driven membenelectromagnetic clutch means for connecting fsaidmembers, said clutch means comprising` a rotatable shell connected tosaid -driving means i andan armatire connected to said driven means andengageable with said shell, said armature being of less-length than thediameter of said shell, said amature furthermore being slotted toprovide a plurality of paths lfor v -magnetic flux and having a shadingcoil around ment with shell 23-and actuatingthe walking one of saidpaths.

y paths.

4. In combination, a driving member, a driven member, andelectromagnetic clutch means for connecting said driven member to saiddriving memben said clutchl means comprising a rotatable shell connectedto said driving member, a

tents. If contactor 6 remains in the same posi-V tion as inthe precedingcycle, said projections merely engage said pointer at the ends of theirmovements without moving the pointer. But if the position of saidcontacter has changed the pointer is shifted by one or'the other ofsaid' projections to designate the correct higher or' lower value. y

It will be seen that therespective coils 24, 2,1, and their armatures29, 39, constitute magnetic clutch elements whereby the indicatorpositioning arms 52, 53 are operated alternatelyby the gears I1, I8, inopposite directions and through complemental extenta'inv each cycle ofrotation'` oi' the transmitter cam 2. By my invention not only is theelement 49 positioned positively vand precisely' in accordance with thequantity values transmitted. but objectionable noise and chatstationaryexciting winding within said shell, and an armature connected to saiddriven member andengageable vwith said shell, said armature comprising amember providingV a plurality of paths ifor 'magnetic fiux and having ashading coil around one of said paths. J

5. In combination, a driving member, a driven member, electromagneticclutchmeans for connecting said members, said clutch means comprising arotatable shell connected to said drivingmember, a stationary' excitingwinding adjacent said shell, and an armature connected to said: driven:member and engageable with said shell; said'armature being of lesslength than thediameter of Asaid shell, said amature furthermore beingslotted to provide a plurality `ot paths for magnetic iiux and Vhaving ashading coil around one of said paths. l

' g IRVING'QMINER.

